More sophisticated driver forms can now be readily produced
with advanced production machinery, leading to a great
variety of head forms for differing purposes
for differing purposes, e.g.
wafer heads – thin and large
diameter to spread the load
over the substrate, which may
be a thin sheet or soft material.
Other common forms
include Narrow/small dia
heads for confined spaces,
Dome heads for aesthetics,
Countersunk heads for smooth
surfaces, Vandal-resistant heads
for security, Integral washers,
Pre-assembled sealing washers,
Load spreading heads and Antivibration,
e.g. serrated flanges.
Generally, in the future the
company foresees evolution
rather than revolution with
major market trends focused on:
• Better production
technologies leading to
better quality, greater
accuracy, cleaner execution,
reduced wastage, lower cost.
• Higher performance
through use of higher spec
materials, better finishes,
superior insertion and drive
capabilities, coupled with
development of new thread
forms to suit different
materials and applications.
As discussed elsewhere,
new thread forms are in
development, but do not seem
to have mass market utility as
yet.This has been the story of
machine screws so far and
Challenge Europe can only see
it continuing as new industries
of personal transit, renewable
energy and recycling continue
to develop new requirements
with ever-lower energy use.
SELF-DRILLING/SELF-TAPPING
SCREWS
Self-drilling/self-tapping
screws for metals and plastics
– ex-stock from Challenge
Europe are often used in the
construction industry, e.g. for
fixing sheet metal in place on
frameworks and can come with
bonded washers to prevent
water ingress in outdoor
applications. Self-drilling
screws come in a variety of
formats but all are based
upon the principle of drilling
and tapping in one operation.
They are generally used in
steel, softer metals or plastics
and there is a range specially
designed for use in wood/
composite materials.
Major benefits in using
this type of fastening include
increased speed of installation
and efficiency provided by
combining the drilling and
tapping operations as well as
a functional improvement in
alignment, which otherwise
could require re-setting the
screw for correct fitment.
Self-tapping screws are
stocked in depth as hardened
and plated carbon steel and
stainless steel self-tappers
for use mainly in sheet steel
products. These screws form
or tap their own thread so
saving time and providing a
strong clamping action with the
ability to remove and replace
if required. Countersunk,
Pan, and Flange heads are
commonly available, the flange
head having the advantage of
spreading the load well and
minimising deformation of
the sheet thus eliminating the
need for an under head washer.
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